Spraying attachment and appliance

ABSTRACT

A nebulizing attachment having a body with an open conical chamber formed therein. The body includes a nozzle with a sharp edge behind which a perforation is formed for supplying air under pressure. Another nozzle is provided in communication with the open conical chamber for supplying liquid therein. The liquid is sucked into the chamber by the effect of vacuum brought about by the passage of the air flow from the nozzle to an outlet therefor. The liquid is fractionated and mixed by the effect of turbulence in this chamber.

TECHNICAL FIELD

The invention presented here involves a nozzle head for the nebulizationof liquids having different viscosities, suited to produce liquidparticles having dimensions less than 1 μm and to diffuse them in orderto form a spray or an aerosol.

The invention presented here also relates to the nebulization deviceequipped with such a nozzle head.

BACKGROUND ART

Nebulization devices are designed to produce a fine particle spray forthe purpose of purification of the atmosphere of place or premises suchas premises that are open to the public. In this application, the sprayformed can have properties of disinfection, deodorization, and at thesame time, the substance sprayed can be a substance that has a smell inorder to put a scent in the atmosphere.

Also, substances can be nebulized that have curative properties. Thus,it is known to use this type of device in medical fields such as theveterinary field notably for the treatment of respiratory canals, forvaccination of animals and for the disinfection of farming areas.

Also, these types of devices can also be used in the form of a spray forthe formation of a mixture of combustive air with a fuel to supplyboilers or even thermal engines.

Other areas of applications of this type of device are also known.

Regardless of the area of application of the device, the results and theefficiencies are even better since the spray is formed from particleshaving a size that is less than a micron, since the size of theparticles is uniform and since the spray has a natural capacity tobecome diffuse and to become uniformly distributed in the volume inwhich it is introduced.

Known devices do not allow the known objectives indicated.

In fact, a size of particles that is not constant as well as in the end,a discharge of the large particles, which is manifest in a loss ofliquid that can be very costly because of condensation on the surfaces,has been observed with these types of devices.

In order to avoid the discharge of large particles, certain nebulizersrequire at the outlet special geometric shapes in order to trap thelarge particles, prohibiting any axial exit of the spray, thus limitingthe possibilities of integrating this type of device in assemblies forconveyance and distribution of the spray formed.

In addition, the particles formed with the devices of the prior art havea greater size such that the spray or the aerosol can be transported,without condensation, over great distances, for example, in an airconditioning network or in tubular elements having internalcross-sections on the order of a half-centimeter. These tubular elementscan be used in order to transport the spray or the aerosol that isformed towards volumes several dozens of meters away from thenebulization device.

With most of these known devices, it is difficult to nebulize, withacceptable results, liquids having an extensive range of viscosity. Infact, these devices only function correctly for a specified range ofviscosity that, moreover, turns out to be very narrow. In addition, thistype of device does not offer the possibility for increasing or reducingthe rated flow without changing the result.

Finally, the devices planned for the formation of particles having asize less than a micron function using very high air pressure.

The invention presented here has the purpose of solving the knownproblems mentioned by implementing a nozzle and a device fornebulization that is suitable for producing particles having a size lessthan 1 μm and to release a spray or an aerosol that is made of particleshaving a uniform size constant in time that can be transported overrelatively sizeable distances without any notable condensation effect inthe transporting conduit.

Another purpose of the invention is to implement a nozzle head and adevice for nebulization that are suitable to nebulize with theequivalent results, liquids having a very extensive range of viscosityand to do this at different flow rates.

Finally, a last purpose of the invention is to implement a nozzle headand a nebulization device suitable for making particles having a sizethat is less than a micron under low air pressure in a range of from 0.5to 8 bars.

SUMMARY OF THE INVENTION

For this purpose, the nebulization nozzle head according to theinvention is made of a body in which an open chamber for mixing andfractionation is formed, consisting of an outlet nozzle and in anopposite manner, at the base, a first nozzle behind which a supply holeis made in the body for gas under pressure, an input of the liquid to benebulized being formed in the body in a manner communicating with thenozzle from the hole, and the input having been connected, by theintermediary of conduits, to a source of gas under pressure and to areservoir of a liquid to be nebulized, the liquid being sucked into themixing and fractionation chamber under the action of the partial vacuumcreated by the passage into it of the gas flow from the first nozzle tothe outlet nozzle and being finely fractionated and mixed with the flowof gas under pressure under the effect of turbulences prevalent in thischamber, which has in front of the first nozzle, a spreading section,characterized in that:

the spreading section is formed by a surface of rotation,

the spreading section and the zone of the first hole situatedimmediately upstream from the spreading section are coaxial,

the introduction is radial in the direction of the flow of the airacross the first nozzle,

a third nozzle is formed at the downstream end of the first hole at thelevel of its intersection with the input of the liquid,

the first and third nozzles are both in contact with the liquid input,are set apart from each other, and are formed by the sharp edges and canbe aligned axially,

the type of the conical jet formed at the outlet of the nozzle head isconical and is made up of fine particles in the center and largeparticles at the periphery.

According to another characteristic of the invention, the liquid inputis formed by at least one cylindrical radial hole terminated by a secondformed nozzle and in the mixing and fractionation chamber and in thefirst hole (8), the geometrical longitudinal axis of symmetry from thezone of the second hole, located immediately upstream from the secondnozzle is contained in the geometric plane containing the first nozzlewhich is defined by a sharp edge formed by the intersection of thespreading section with the upstream zone of the first hole.

the longitudinal axis of symmetry of the zone of the second hole locatedimmediately upstream from the second nozzle is secant and perpendicularto the axis of symmetry of the spreading section.

Using these devices, at the output of the nozzle head, a conical jet isobtained which is made of fine particles having a size less than amicron, in a large number, and larger particles that are larger and thusheavier, in a reduced number.

The characteristics of the nozzle head make it so that a mixture ofthese particles is obtained that is non-homogeneous; the heaviestparticles are located in the peripheral zone of the conical jet whilethe particles that are finer, and thus lighter, are located in thecentral zone.

Thus, already at the outlet of the nozzle head for nebulization and dueto the characteristics of this nozzle head, the separation between thelarge particles to be extracted from the spray and the fine particles isdone before the spray is formed.

In order to further improve this result, the spreading section extendsevenly from the first nozzle to the outlet nozzle, i.e. over the entirelength of the mixing and fractionation chamber, and it preferably hasthe shape of a truncated cone whose angle to the peak is made in a rangefrom ten to ninety degrees. Excellent results have been obtained with anangle to the peak equal to sixty degrees. It goes without saying thatthese values are only given as a rough guide; the angle to the peak canbe less than ten degrees or greater than ninety degrees.

The length of the chamber can be limited to a few millimeters, forexample, to six millimeters, this length being sufficient in order toform a turbulence zone of sufficient size in order to ensure theseparation of the particles.

It is noted that the turbulences are created essentially at the level ofthe two nozzles for the input of the liquid and compressed gas, due tothe irregularity of the surface that is present at this level and due tothe sharp edge that demarcates the nozzle from the compressed gas input.

Another factor that contributes to the creation of the turbulences isthe imbalance of the jet formed, i.e. its offset relative to the axis ofsymmetry of the spreading section, this offset being due essentially tothe presence of a unique nozzle for the liquid input.

In order to improve the flow rate while maintaining this imbalance, theinvention, according to another of its characteristics, provides severalsecond nozzles distributed in an irregular manner around the axis ofsymmetry of the mixing and fractionation chamber.

As a variation, a regular distribution can be provided, but with nozzleshaving different diameters.

According to another characteristic of the invention, the zone of thefirst hole, located immediately upstream from the first nozzle, and thezone of the second hole, located immediately upstream from the secondnozzle, are both cylindrical. Moreover, the zone of the first hole,located immediately upstream from the first nozzle has a diameter thatis smaller than the diameter of the zone of the second hole, locatedimmediately upstream from the second nozzle.

Purely as a rough guide, these zones have diameters that are roughlyequal to 400 μm and to 800 μm, respectively. It goes without saying thatthese values are only given purely as a rough guide, the respectivevalues of the diameters of the two zones can be less than or greaterthan the values indicated.

By these relatively standard dimensions in the field of precisionmechanics, it is thus possible to create nozzles fitted to createparticles less than 1 μm and this is done with the manufacturingtolerances standard in this field.

This is due to the fact that producing particles all having a size lessthan a micron at the output of the nebulization nozzle head had not beenresearched essentially with a view to efficiency and simplification ofthe creation, but on the contrary, unpredictably producing fineparticles and coarse particles. The only requirement was that the fineparticles that have dimensions less than a micron be sufficient innumber in order to form a sufficiently dense spray in order to be used.

In order to greatly reduce the number of the large particles in the jetemitted by the nebulization nozzle head, according to anothercharacteristic of the invention, above the outlet nozzle, at a distancefrom it, a deflector plane is mounted, where this deflector isperpendicular to the axis of symmetry of the chamber and centeredrelative to it. The deflector has a length and width greater than thediameter of the nozzle at the output and being notably designed to turndown the jet laterally towards the edge forming the nozzle at the outletof the mixing chamber. This device makes it possible to create at thislevel, i.e. on the outlet nozzle, a fractionating of the largeparticles. In order to reinforce this result, the outlet nozzle isformed by a sharp edge. If desired, the deflector is designed to catchand deflect the large particles.

The size of the particles formed depends closely on the distance betweenthe deflector and the nozzle of the outlet. As a guideline, thisdistance will be greater than 5 μm and can be between 100 μm and 5 mm.Depending on the case, the distance between the deflector and the outletnozzle can be fixed or even adjustable in order to regulate the size ofthe particles emitted and to adapt the spraying nozzle head to theviscosity of the liquid to be nebulized. The distance between thedeflector and the outlet nozzle determines the flow rate of thenebulization. In an unexpected manner, a low distance corresponds to asizeable flow rate.

Excellent results have been obtained with a distance of 150 μm.

Finally, the nebulization nozzle head, according to another embodimentform, can be provided with a hole planned for the vacuum extraction ofresidual flows, this second hole opening on the one hand, into themixing and fractionation chamber and on the other hand, on one of thesides of the body of the nozzle head where it forms at this level avacuum extraction opening of the residual flows of the liquid formed bythe large particles.

The different characteristics of the nebulization nozzle head such asthe ones that have just been listed allow nebulization with identical orat least, comparable, results for liquids having viscosities that arevery far apart such as aqueous solutions and oils and this is done undera range of gas pressure and thus of flow rate, which as far as it isconcerned is very extensive, for example, pressures from 0.5 bars to 8bars.

In addition, the reduced length of the fractionation and mixing chamberfrom the nebulization nozzle head makes it possible to produce aneffective response to the dimensional restrictions posed by theimplantation in the devices of nebulization having a reduced size.

The nebulization device according to the invention is characterizedessentially in that it is equipped with at least one nebulization nozzlehead as described above.

This device, according to another characteristic, consists of a hollowbody at the base of which and in which at least one nebulization nozzlehead is mounted relative to on the one hand, a source of compressed gasby the intermediary of a conduit and on the other hand, with a reservoirof a liquid to be nebulized, mounted under the body, where thenebulization nozzle head, by its outlet nozzle, is in communication withan expansion chamber made in the body of the device, coaxial to themixing and fractionation chamber of the nebulization nozzle head, theinternal side of the chamber receiving the large particles emitted bythe jet and catching them, so that they flow under the action of theirweight on this side, towards the reservoir.

When the nozzle head is equipped with the deflector, the nebulized jetis caused to spin around in the expansion chamber. This is due to thesloped surface of the nozzle head whose main role is to conduct anddirect this jet.

The jet of particles emitted by the nebulization nozzle head, as far asthe peripheral zone of it is concerned, i.e. the one formed by the largeparticles, is oriented towards the inner side of the expansion chamberin a manner such that the large particles are caught by it.

According to another characteristic of the invention, the expansionchamber as opposed to the nebulization nozzle head, is limited by atransverse wall perpendicular to the geometric axis of the fractionationchamber, this wall contains in its center a hole that passes through thenebulization outlet. The height of this transverse wall relative to thespraying nozzle head as well as the diameter of hole passing through canvary as a function, for example, of the physical characteristics of theliquid to be sprayed.

According to yet another characteristic of the invention, the externalside of the nebulization chamber, of the transverse wall, is convex andthis wall consists of indentations on its periphery. This arrangementallows the flow towards the expansion chamber of any condensate formedabove or on the transverse wall.

The inner side of the expansion chamber can be smooth, or even beequipped with one or more projections or hollows.

However, to the extent the configuration of the inner side of thechamber is smooth or has relief, it leads to a loss of a sizeable load.

From this loss of load, a drop in the speed of the progression of thespray of micro-particles results in the device, along with a risk ofdeposit and condensation, over time, of these micro-particles on theinner side of the body and as a consequence, a risk of driving theparticles having a larger size into the jet of micro-particles.

In order to compensate for this disadvantage, according to anothercharacteristic of the invention, the expansion chamber is extended by atleast one acceleration zone of movement of the spray of particles inorder to increase the speed of the spray and avoid any deposition offine particles, the aforementioned zone being in contact with an outletconduit of the spray or the aerosol formed.

The speed of the particles in the acceleration zone is sufficientlysizeable in order to prevent them from being caught and condensingagainst the walls of the hollow body.

In the preferred embodiment form, the acceleration zone of movement ofthe spray is in contact with the expansion chamber by a passage having asmaller cross-section than the cross-section of the chamber, thispassage having a smaller cross-section can be formed, when the expansionchamber is limited by the transverse wall, by the hole passing throughthe wall.

This passage having a reduced cross section is favorable itself on theoutlet, to emit a jet at an increased speed.

According to another embodiment form of the invention, the expansionchamber, as opposed to the nebulization nozzle head, contains a blockagewall and the wall of the reservoir, and above the maximum level of theliquid, is equipped with an outlet nozzle of the spray or aerosol. Thisembodiment form, which no longer provides the upper acceleration zone,enables the creation of a particularly compact device.

According to another characteristic of the invention, the body of thedevice, between the reservoir and the expansion chamber, is equippedwith a transversal partition that carries the nebulization nozzle head.This partition, for a device equipped with an upper acceleration zone,ensures the air-tightedness between the expansion chamber and the zoneof the reservoir located above the level of the liquid. This deviceprevents that under the effect of the pressure, the spray of particlesis led towards the bottom and into the reservoir, which would weaken theefficiency of the device as a consequence.

For a device whose spray or aerosol outlet is guided into the wall ofthe reservoir, the partition will be equipped with a communicationopening of the expansion chamber with the volume of the reservoirlocated above the level of the liquid.

According to another characteristic of the invention, the nebulizationdevice is equipped with a mechanism for evacuation towards the reservoirthe residual flows of the liquid formed by the large particles in theexpansion chamber. This device prevents blocking of the expansionchamber by the flows.

According to another characteristic of the invention, the evacuationmechanism of the residual flows towards the reservoir passes throughboth sides of the partition. This mechanism, by its lower end, islocated below the minimum level of liquid in the reservoir. This device,which provides a mechanism for the internal evacuation of the device,also leads to a better compactness of the device.

For a device whose expansion chamber is separated in an airtight mannerfrom the zone of the reservoir located above the level of the liquid,the evacuation mechanism towards the reservoir, of the residual flows ofliquid formed by the large particles, is made up of at least one tubeengaged in a hole made in the transverse partition, where the partitionand the tube ensure more separation between the volume of the reservoirlocated above the level of the liquid and the expansion chamber.

For a device whose expansion chamber is in communication with the zoneof the reservoir located above the level of the liquid, the evacuationmechanism is made up of a blade engaged in the communication opening.

For a device equipped with a transverse partition ensuring the airtightseparation between the expansion chamber and reservoir for the liquid tobe nebulized, it is also possible to prevent the blocking of thischamber by the accumulation of residual flows using a nebulizationnozzle head equipped with a vacuum extraction hole opening on one of thesides of the body of the nozzle head.

BRIEF DESCRIPTION OF THE DRAWINGS

Other goals, advantages and characteristics of the invention appear inreading the description of the preferred embodiment forms given asnon-restrictive examples in referring to the attached drawings, inwhich:

FIG. 1 is a view in a longitudinal section of a nebulization nozzle headaccording to a first embodiment form,

FIG. 2 is a side elevational view of the nebulization nozzle head of thefirst embodiment of the present invention.

FIG. 3 is a sectional view of a nozzle head according to anotherembodiment form,

FIG. 4 is a sectional view of a nebulization nozzle head with a radialhole for the vacuum extraction of the residual flows,

FIG. 4a is a sectional view of a nebulization nozzle head with a radialhole for the vacuum extraction of the residual flows according to asecond embodiment form,

FIG. 5 is a longitudinal sectional view of a device according to a firstembodiment form,

FIG. 6 is a longitudinal sectional view of a nebulization deviceaccording to a second embodiment form,

FIG. 7 is a plan view of the nebulization device of FIG. 6.

FIG. 8 is a sectional view of a device according to a fourth embodimentform,

FIG. 9 is a sectional view of a device according to a fifth embodimentform,

FIG. 10 is a longitudinal sectional view of a device according to asixth embodiment form.

FIG. 11 shows, seen from above, an arrangement of the nebulizationnozzle heads according to a first embodiment form,

FIG. 12 shows, seen from above, an arrangement of the nebulizationnozzle heads according to a second embodiment form.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a nebulization nozzle head 1 according to a firstembodiment form of the invention.

This nozzle head includes a body formed from two cylindrical forms 2, 3axially aligned, having different diameters, separated from each otherby a shouldered surface 4, the diameter of the cylindrical form 3 beingless than the diameter of the cylindrical form 2. Along the longitudinalaxis of the body, in the cylindrical form 2, from the front side of it,a mixing and fractionation chamber 5 is made using any known methods, inthe form of an inverted truncated cone, the large base of the truncatedcone being located in the front side and being limited by a sharpcircular edge that forms the outlet nozzle 6 of the nozzle head 1.Preferably, the outlet nozzle 6 is contained in a plane that is normalto the axis of symmetry of the chamber 5. Around the outlet nozzle 6,the body of the nozzle head has a sloped surface 7 that forms atruncated cone. This sloped surface, in allowing the flow of the largeparticles towards the base where they accumulate, prevents them frombeing guided into the jet. In the axis of the mixing and fractionationchamber 5, the second cylindrical form 3 is passed through on both sidesby a hole 8, or first hole. This hole opens into the mixing andfractionation chamber 5 in order to form there, following the small baseof the truncated cone shape of this chamber, a first nozzle 9 defined bya sharp edge and contained in the geometric plane perpendicular to thelongitudinal axis of symmetry of the chamber 5. The hole passing through8 ends immediately upstream from the nozzle 9 with a zone 8 a having asmaller diameter, on the order, for example, of 400 μm, and the diameterof the first nozzle 9 is equal to this value. The length of the zone 8 adetermines the range of functioning pressures, i.e. the pressure of thegaseous fluid upstream from the hole 8. Thus, with a length of 5 to 6mm, the functioning range consists of between 0.5 bars and 3.5 bars,with a length of 2 mm it consists of between 2 and 6 bars. Below theminimum values, the Venturi effect does not occur. Above the maximumvalues, the nebulization no longer occurs; a part of the gaseous fluidrushes into the input 10 of the liquid and pushes the liquid backtowards the reservoir.

The second cylindrical form 3 forms a channel and is designed to beconnected by a conduit to a source for the distribution of gas underpressure. This gas can be air.

According to the geometrical plane of the first nozzle 9, the firstcylindrical form is provided in a radial cylindrical hole 10 whoselongitudinal axis of symmetry is radial to the first nozzle. This secondhole opens into the mixing chamber and into the zone 8 a of the firsthole and forms at this level a second nozzle 11 extending on both sidesof the geometric plane of the first and a third nozzle 9′ resulting fromthe intersection of the cylindrical surface of the second hole with thecylindrical surface of the first hole. Immediately upstream from thesecond hole 11, the radial hole 10 has a zone having a lower diameter 10a, the value of the diameter of this zone being, for example, on theorder of 800 μm. As opposed to the nozzle 11, the radial hole 10 isblocked by an appropriate stopper. As an example, this stopper will bethreaded and engaged in a tapped hole made in the radial hole. From theshouldered side, a supply hole 12 opening into the hole 10 is made inthe first cylindrical form, parallel to the longitudinal axis of it. Inthis hole 12, from the shouldered surface 4, a threaded countersinkingis made into which the threaded end of a vacuum extraction tube 13, of aliquid to be nebulized, can be screwed.

By passage of the compressed air from the nozzle 9′ to the nozzle 9, atthe level of the nozzle 11, a partial vacuum is created under the actionof which if the speed of the compressed air is sufficiently high, theliquid to be nebulized is vacuum extracted in the tube 13 as well as inthe holes 12 and 10 in order to reach the nozzle 9 and then fractionateand mix with the air flow in the truncated cone spreading section thatforms the chamber 5.

This nebulization nozzle head as described emits at the outlet a sprayin the form of a conical jet that contains the large particles in theperipheral zones and particles having a size less than 1 μm in thecentral zones.

In FIG. 2 you can see that the nebulization nozzle head according to theinvention is equipped with a deflector 14 that appears, for example, inthe form of a rectangular planar blade that has length and width greaterthan the diameter of the outlet nozzle. This deflector 14 is parallel tothe, plane of the outlet nozzle 6 and is maintained in a centered mannerrelative to the longitudinal axis of symmetry of the chamber 5. Inaddition, in order to allow the adjustment of the size of the particlesand the emission of particles having sizes fitted to the plannedapplication, the distance between the deflector 14 and the outlet nozzleis controllable. A low distance, on the order of a dozen millimeters,corresponds to the formation of fine particles due to the increase ofturbulence in the chamber which supports the fractionation, while alarge distance on the order of a half-centimeter corresponds to areduction of the size of the turbulence in the chamber, and thus lessfractionation of the particles.

The nebulization nozzle head, as just described, can be equipped as seenin FIG. 4, with at least one radial hole 2 a opening on the one hand, inthe mixing and fractionation chamber 5 and on the other hand, on thecylindrical face of the first cylindrical form 2 of the body of thenozzle head where it forms at this level a vacuum extraction opening forthe residual flows of liquid formed by the large particles. Thus, anyaccumulation of residual flow is vacuum extracted in the nozzle head inorder to undergo nebulization again in the fractionation chamber 5.

As a variation, as shown in FIG. 4a, the hole 2 a that has a verticalpart in order to not open into the cylindrical face of the firstcylindrical form of the body of the nebulization nozzle head but into anindentation that it has in the lower part. According to this embodimentform, the vacuum extraction of the residual flows occur from theindentation.

Shown in FIG. 3 is a nozzle head according to another embodiment form.You can see that the input 10 of the liquid extends between and aroundthe nozzles 9 and 9′, where they are preferably set off at a distance bya value of a few dozen millimeters. Preferably, without beingrestrictive, the nozzles 9 and 9′ each of which are always defined by asharp edge, have the same diameter. This nozzle head is made of a bodyin two parts assembled to each other in a manner so that they can bedisassembled. The mixing and fractionation chamber 6 as well as theinput 10 are formed in the first part of the body while the second partof the body is equipped with the first hole 8 and conduits connectingthe hole 8 and input 10 to the source of the gas under pressure and tothe reserve of the liquid to be nebulized. Preferentially, the input 10is made up of a cylindrical chamber arranged at the base of the firstbody of the nozzle head. During the assembly of the two parts of thebody of the nozzle head, the cylindrical chamber is positioned relativeto a surface junction plane that contains the second part of the body ofthe head. Always depending on the preferred form of the invention, thehole 8 is formed in a detachable nozzle 32 introduced into a housing ofthe second part of the body, formed in a manner passing through from thesurface junction plane to a blind passage connected by any appropriatemeans to the source of the compressed gas. This detachable nozzle as canbe seen in FIG. 3 includes a cylindrical nozzle head housed in acountersink of the housing. The head of the nozzle contains around thenozzle 9′ a sloped surface in a truncated cone that forms a projectionon the surface of the junction. You can notice that the cylindricalsurface of the head is completely housed in the countersinking, the onlyprojecting shape is the sloped surface. This arrangement makes itpossible to guide the liquid to be nebulized to the compressed air flowpassing from the nozzle 9′ to the nozzle 9.

FIG. 5 shows a nebulization device 15 according to a first embodimentform.

This device contains at least one nebulization nozzle head 1 accordingto one type of embodiment and containing a hollow body 16 at the base ofwhich at least on nebulization nozzle head 1 is mounted that is suppliedwith compressed gas, for example, air, by a conduit 17 connected to asource of compressed gas. The nozzle head is supplied with liquid to benebulized by the vacuum extraction tube 13, this tube sticking into theliquid reservoir 18 mounted under the body 16 and separated from it by atransverse partition 19 that supports the nebulization nozzle head 1.The jet of particles produced by the head 1 is admitted into theexpansion chamber 20 formed in the body, above the transverse partition19. As opposed to the nebulization head, the body of the device isequipped with a hole passing through, tapped in which is engaged thethreaded tip of an outlet tube 16 a of the particle spray.

In the preferred embodiment form, the expansion chamber 20 is in acylindrical shape but as a variation, the form of the chamber can beparallelepiped. The expansion chamber 20 and the mixing andfractionation chamber 5 of the nebulization nozzle head are coaxial withrespect to each other. Always according to the preferred embodimentform, the partition 19 is provided with a nozzle passing through and ablind nozzle that are parallel to each other, the blind nozzle beingmade in the wall 19 from the side turned toward the expansion chamber.In these nozzles, with the interposition of toroid airtight seals, onthe one hand, the vacuum extraction tube 13 and on the other hand, thesecond cylindrical shape 3 of the body of the nozzle head arerespectively engaged. The blind nozzle is in communication with a radialhole made in the transverse wall from the outside of the body of thedevice. This radial hole is in communication with a conduit (not shown)connected to a source of compressed air in order to ensure the supply ofthe nebulization nozzle head with compressed air.

The expansion chamber 20 is preferably defined by the internal volume ofthe body of the device.

Preferably, the expansion chamber 20 in contrast to the nebulizationnozzle head 1 is defined by a transversal wall 21 perpendicular to thegeometric axis of the fractionation chamber of the nozzle head, wherethis wall at its center contains an opening 22 that passes through thenebulization outlet.

Advantageously the outer side of the nebulization chamber, of thetransversal wall 21 is convex and contains indentations in itsperiphery. This arrangement allows the gravitational flow, towards theexpansion chamber and towards the reservoir, of possible liquidcondensates formed above the wall or even on the convex side.

In the embodiment form that is shown in FIG. 5, the expansion chamber 20is extended axially towards the outside by a zone 23 for acceleratingthe movement of the spray of particles in order to increase their speedand prevent any deposition of the particles on the sides of the insidevolume of the body of the device.

According to a preferred embodiment, the acceleration zone 23 isconnected to the expansion chamber 20 by a passage 24 having a smallercross-section than the cross-section of the chamber. This passage 24 ismade, for example, by a hole that passes through and is formed in apartition 25 extending transversally in the hollow body and held fixedin the body against the upper edge of the tubular sheath 20 a or at adistance from it. This hole 24 passing through can be formed by anoblong aperture but any other form of the hole could be appropriate.Advantageously the acceleration zone consists of at least two partitions25 with openings going through them, mounted at a distance from eachother, the opening passing through one being shifted angularly by ninetydegrees relative to the opening passing through the other one in orderto make the jet undergo a rotation between the two partitions by aquarter turn, which increases the tangential speed of the particles andreduces the risk of agglomeration of these particles on the sides of theinner volume of the body of the device. These partitions 25 can be keptat a distance from each other on the hand, and at a distance from thesheath 20 a on the other hand, by a set of several tubular distancesleeves 26 mounted in the inner volume of the body of the device.

The nebulization device according to FIG. 6 is no longer equipped withthe upper acceleration zone arranged above the expansion chamber 20 andthis expansion chamber, in contrast with the nebulization nozzle head 1,has a blocking wall 27 affixed in a known manner in itself at the upperedge of the tubular sheath 20 a. According to this variation, thetransversal partition 19 is provided with an opening 28 forcommunication of the expansion chamber 20 with the volume of thereservoir located above the level of the liquid and the wall of thereservoir 18, above the maximum level of the liquid, is equipped with atapped hole into which the threaded tip of an outlet conduit 29, for thespray or aerosol formed, can be screwed. The communication opening 28will be arranged in the partition 19 around the body of the nebulizationnozzle head 1 according to a circumferential circular arc.

Preferably, the nebulization device, according to one or the otherembodiment form as described, is equipped with a mechanism forevacuation towards the reservoir, of the residual flows of the liquidformed by the large particles in the expansion chamber: preferably, thismechanism passes straight through the partition and comes at its lowerend below a minimum level of the liquid in the reservoir.

For the device according to FIG. 5, the evacuation mechanism consists ofat least one vertical tube 30 engaged at its upper end in a hole passingthrough that is made in the partition 19, this partition 19 and the tube30 ensuring in addition the airtight separation between the volume ofthe reservoir located above the level of the liquid and the expansionchamber. By its lower end, the tube 30 comes below the minimum level ofthe liquid in the reservoir 18. For a complete evacuation of theresidual flows, several holes passing through, which are each connectedto an evacuation tube appropriate for them, can be provided in thepartition 19, around the body of the nebulization nozzle head.

For the device according to FIG. 6, the evacuation mechanism will bemade up of a vertical blade having a small thickness, engaged at itsupper end in the communication opening and pinned against one of thelongitudinal edges of the opening completely covering it. The residualliquid in sliding over this blade is conducted by dripping down towardsthe reservoir 18 and the liquid contained in it.

FIG. 8 shows in a partial manner a nebulization device whosenebulization nozzle head is equipped with a hole 2 a for vacuumevacuation of the residual liquid. This hole can open in the cylindricalside of the first cylindrical form of the body of the nozzle head oreven a variation, as shown in FIG. 4a, having a vertical part in orderto open into an indentation arranged in the first cylindrical form.According to one or the other of these two embodiment forms, the deviceis equipped with a partition 19 that ensures an airtight separationbetween the reservoir in its assembly and the expansion chamber. Thedevice according to this embodiment form is not equipped with amechanism for evacuation to the reservoir of the residual flows, whichsimplifies its creation.

In FIG. 9 a nebulization device is shown that is free from the partition19. In this embodiment form, the inside volume of the reservoir isdirectly in communication with the expansion chamber 20 and containsprojecting on its base a cylindrical protuberance supporting thenebulization nozzle head 1. The nebulization nozzle head 1 does notcontain a supply hole and the radial hole 12 now opens onto thecylindrical side of the first cylindrical form-of the nozzle head 1 inorder to form at this level a nozzle located above the level of theliquid in the reservoir. This nozzle head can also be equipped with ahole for vacuum extraction of the residual liquid, which opens either inthe cylindrical side of the first cylindrical form of the body of thenozzle head, or in an indentation formed on the lower part. Moreover,the hole 12 can contain a vertical part and not open in the cylindricalsurface of the first cylindrical form of the body of the nozzle head,but in an indentation formed in the lower part of the body of the firstcylindrical form of the body of the nozzle head.

The device is connected to the mechanisms to keep constant the level ofthe liquid in the reservoir, these mechanisms can includes a storagecapacity 46 of the liquid to be nebulized, outside of the device and ofa pump 47 whose extraction opening is connected by an appropriateconduit to the internal volume of the storage capacity. By theintermediary of an appropriate conduit, the delivery opening of the pumpis connected to the inside volume of the reservoir 18. The flow rate ofthe pump can be fixed to the flow rate of the nebulized liquid or eventhe sensors of the level, not shown, connected to a control circuit forstarting or stopping the function of the pump 47, can be arranged in thereservoir. In this embodiment form, the residual of the liquid fallsdirectly back into the reservoir 18. According to this embodiment form,the nebulization nozzle head is supplied with compressed air by avertical channel 48.

In order to prevent the presence of the sensor at the level in theliquid reservoir, a device can be provided with a partition 19, mountedin a manner sliding in the reservoir like a piston. In this embodimentform, as shown in FIG. 10, the device 15 contains an externalcylindrical surface and slides with a little play, by this cylindricalexternal surface, in the cylindrical bore of the reservoir 18. The lowerpart of the body of the device and more particularly the partition 19 isconstructed as a piston and contains one or more annular, airtightsegment(s). According to this embodiment form, the supply of compressedair is no longer carried out by a radial opening made in the partition19, but by a rigid cannula 49, in communication with the hole 8 of thebody of the nebulization nozzle head by the intermediary of an axialhole passing through, made in the partition 19. This cannula 49 extendsinto the reservoir 18 along the direction of the sliding of the body ofthe device and is engaged in sliding in a bore made in the wall of thebase of the reservoir. Airtight annular seals are arranged in the borein order to avoid any leakage of the liquid at this level. On theoutside of the reservoir, the cannula is connected by a flexible conduitto a source for the distribution of air under pressure. The deviceaccording to this embodiment form is carried along by the liquid presentin the reservoir 18. Thus, the degree to which the body of the device ispushed into the reservoir depends on the quantity of the liquidcontained in it. Due to this fact, by the measure or the detection ofthe degree to which it is pushed in, it is possible to detect thequantity of liquid in the reservoir and if the level is very low, torestock the liquid in an automatic manner with the help of a pump 50that has an opening for pumping out the liquid. The opening is connectedby an appropriate conduit to the internal volume of a liquid reserve 51.The delivery opening this pump is connected to the internal volume ofthe reservoir 18 by the intermediary of an appropriate conduit. Thispump 50 will be activated by an electric motor, controlled by a circuitthat has automatic functioning and power, containing notably outside thereservoir 18, two sensors at the level 52, 53 at a distance from eachother and both arranged in the path of an activation contact 54 carriedby the cannula. The sensor closest to the reservoir or the first sensor,emits when it is activated a signal representing a maximum level of theliquid in the reservoir 18, while the second sensor emits when it isactivated a signal representing a minimum level of the liquid. Theapplication of the latter signal on the corresponding input of theautomatic functioning and power circuit commands the closing of thesupply circuit of the electric motor for activating the pump and thusthe activation of the pump 50. The pump then pumps out the liquidcontained in the reserve 51 and delivers it to the reservoir 18. Theliquid introduced progressively pushes back the device 15 to itsposition of being set back less into the reservoir, realized by theposition of the first sensor. When this latter is activated by thecontact block 54 carried by the shaft 49, the signal emitted and appliedon the corresponding input of the circuit for automation and power, thisis manifest by the opening of the power supply circuit of the electricmotor and thus deactivation of the pump.

According to another embodiment mode, the mechanism for maintainingconstant level of the liquid in the reservoir 18 can be made by anadditional reservoir, airtight, adjoined to the device and provided inthe lower part with an outlet nozzle connected by a conduit to an inputnozzle of the liquid that the reservoir 18 contains in the lower part.

The device, in the different embodiment forms as described, can beequipped with several nebulization nozzle heads 1 supplied with liquidto be nebulized from a same reservoir and made of compressed gas from asame source of pressure.

In FIG. 11, a first arrangement of the nozzle head is shown. Accordingto this embodiment, the nebulization nozzle heads 1 are distributed atregular or irregular intervals along a circle, whose center, forexample, will be located on the geometric median vertical axis of theexpansion chamber. This arrangement is most especially suited for usewith an expansion chamber having a cylindrical form.

In FIG. 12, a second arrangement of the nebulization nozzle head isshown. According to this embodiment form, the nebulization nozzle headsare distributed at regular or irregular intervals along a straight line.This arrangement can be used with an expansion chamber having arectangular cross-section, for a better efficiency, the alignment formedby the nebulization nozzle heads goes along the direction of the lengthof the this cross-section.

The angle of inclination of each nozzle head relative to a reference canbe fixed or even variable.

I claim:
 1. A nebulization device comprising: a hollow body having abase; a nebulization nozzle head mounted on said base, said nozzle headhaving an open chamber for mixing and fractionating, said open chamberhaving an outlet nozzle and a first nozzle opposite to said outletnozzle, a supply hole formed behind said first nozzle, said nozzle beadhaving an inlet formed therein in communication with said first nozzle;a source of compressed gas connected by a supply conduit to said supplyhole; a reservoir containing a liquid to be nebulized, said reservoirmounted under said hollow body, said nozzle head having said outletnozzle in communication with an expansion chamber formed in said hollowbody coaxial with said open chamber, the liquid being sucked into saidopen chamber, the liquid being sucked into said open chamber by apartial vacuum created by a gas flow from said first nozzle to saidoutlet nozzle, the liquid being fractionated and mixed with the gas flowby turbulence in said open chamber, said open chamber having a spreadingsection in front of said first nozzle, said spreading section having asurface of rotation, said spreading section and a zone of said supplyhole being coaxial, said inlet being radial to the air flow across saidfirst nozzle; a third nozzle formed downstream of said supply hole at anintersection of said supply hole with said inlet, said first and thirdnozzles both being in contact with said inlet and spread apart from eachother, said first and third nozzles being formed by sharp edges andaxially aligned, said outlet nozzle being a conical jet having fineparticles in a center thereof and large particles around a peripherythereof, said expansion chamber receiving the large particles emitted bysaid jet such that the large particles flow by gravity toward a bottomof said expansion chamber, said expansion chamber having a transversewall opposite said nozzle head, said transverse wall being perpendicularto said open chamber, said transverse wall having a hole at a centerthereof passing through said outlet nozzle, said wall having a convexouter side.
 2. A nebulization device comprising: a hollow body having abase; a nebulization nozzle head mounted on said base, said nozzle headhaving an open chamber for mixing and fractionating, said open chamberhaving an outlet nozzle and a first nozzle opposite to said outletnozzle, a supply hole formed behind said first nozzle, said nozzle headhaving an inlet formed therein in communication with said first nozzle;a source of compressed gas connected by a supply conduit to said supplyhole; a reservoir containing a liquid to be nebulized, said reservoirmounted under said hollow body, said nozzle head having said outletnozzle in communication with an expansion chamber formed in said hollowbody coaxial with said open chamber, the liquid being sucked into saidopen chamber, the liquid being sucked into said open chamber by apartial vacuum created by a gas flow from said first nozzle to saidoutlet nozzle, the liquid being fractionated and mixed with the gas flowby turbulence in said open chamber, said open chamber having a spreadingsection in front of said first nozzle, said spreading section having asurface of rotation, said spreading section and a zone of said supplyhole being coaxial, said inlet being radial to the air flow across saidfirst nozzle; and a third nozzle formed downstream of said supply holeat an intersection of said supply hole with said inlet, said first andthird nozzles both being in contact with said inlet and spread apartfrom each other, said first and third nozzles being formed by sharpedges and axially aligned, said outlet nozzle being a conical jet havingfine particles in a center thereof and large particles around aperiphery thereof, said expansion chamber receiving the large particlesemitted by said jet such that the large particles flow by gravity towarda bottom of said expansion chamber, said expansion chamber having ablocking wall opposite said nozzle head, said reservoir having a wallpositioned above a highest level of the liquid to be nebulized, saidwall of said reservoir having an outlet nozzle.
 3. A nebulization devicecomprising: a hollow body having a base; a nebulization nozzle headmounted on said base, said nozzle head having an open chamber for mixingand fractionating, said open chamber having an outlet nozzle and a firstnozzle opposite to said outlet nozzle, a supply hole formed behind saidfirst nozzle, said nozzle head having an inlet formed therein incommunication with said first nozzle; a source of compressed gasconnected by a supply conduit to said supply hole; a reservoircontaining a liquid to be nebulized, said reservoir mounted under saidhollow body, said nozzle head having said outlet nozzle in communicationwith an expansion chamber formed in said hollow body coaxial with saidopen chamber, the liquid being sucked into said open chamber, the liquidbeing sucked into said open chamber by a partial vacuum created by a gasflow from said first nozzle to said outlet nozzle, the liquid beingfractionated and mixed with the gas flow by turbulence in said openchamber, said open chamber having a spreading section in front of saidfirst nozzle, said spreading section having a surface of rotation, saidspreading section and a zone of said supply hole being coaxial, saidinlet being radial to the air flow across said first nozzle; a thirdnozzle formed downstream of said supply hole at an intersection of saidsupply hole with said inlet, said first and third nozzles both being incontact with said inlet and spread apart from each other, said first andthird nozzles being formed by sharp edges and axially aligned, saidoutlet nozzle being a conical jet having fine particles in a centerthereof and large particles around a periphery thereof, said expansionchamber receiving the large particles emitted by said jet such that thelarge particles flow by gravity toward a bottom of said expansionchamber, said hollow body being positioned between said reservoir andsaid expansion chamber, said hollow body having a transversal partition,said transversal partition carrying said nozzle head; and an evacuationmeans for passing a residual flow of liquid toward said reservoir, saidevacuation means extending through said transversal partition, saidevacuation means having a lower end located below a minimum level of theliquid in said reservoir, said evacuation means comprising at least onetube engaged within a hole formed in said transversal partition, saidpartition and said tube separating in airtight relationship to aninterior volume of said reservoir and said expansion chamber in an areaabove a maximum level of the liquid in said reservoir.
 4. A nebulizationdevice comprising: a hollow body having a base; a nebulization nozzlehead mounted on said base, said nozzle head having an open chamber formixing and fractionating, said open chamber having an outlet nozzle anda first nozzle opposite to said outlet nozzle, a supply hole formedbehind said first nozzle, said nozzle head having an inlet formedtherein in communication with said first nozzle; a source of compressedgas connected by a supply conduit to said supply hole; a reservoircontaining a liquid to be nebulized, said reservoir mounted under saidhollow body, said nozzle head having said outlet nozzle in communicationwith an expansion chamber formed in said hollow body coaxial with saidopen chamber, the liquid being sucked into said open chamber, the liquidbeing sucked into said open chamber by v partial vacuum created by a gasflow from said first nozzle to said outlet nozzle, the liquid beingfractionated and mixed with the gas flow by turbulence in said openchamber, said open chamber having a spreading section in front of saidfirst nozzle, said spreading section having a surface of rotation, saidspreading section and a zone of said supply hole being coaxial saidinlet being radial to the air flow across said first nozzle; a thirdnozzle formed downstream of said supply hole at an intersection of saidsupply hole with said inlet, said first and third nozzles both being incontact with said inlet and spread apart from each other, said first andthird nozzles being formed by sharp edges and axially aligned, saidoutlet nozzle being a conical jet having fine particles in a centerthereof and large particles around a periphery thereof, said expansionchamber receiving the large particles emitted by said jet such that thelarge particles flow by gravity toward a bottom of said expansionchamber, said body having a partition in a lower part thereof, saidsource of compressed gas comprising a rigid cannula in communicationwith said supply hole, said rigid cannula extending through an axialhole formed in said partition, said cannula extending through the baseof said reservoir into said reservoir along a direction of movement ofsaid hollow body, said cannula slidable in a bore formed in a wall of abase of said reservoir, said cannula connected to a flexible conduitexterior of said reservoir, said flexible conduit connected to saidsource of compressed air; a pump means having an opening for pumping outthe liquid from a liquid reserve, said pump means connected by a conduitto the liquid reserve, said pump means having a delivery openingconnected by another conduit to said reservoir; and an electric motormeans connected to said pump means for actuating said pump means, saidelectric motor means having two sensors exterior of said reservoir, saidtwo sensors spaced from each other, said two sensors positioned along apath of an activation contact by said cannula.